Ash remover for stokers



June 24', 1952 c. E. SHAFFER 2,501,332

ASH REMOVER FOR STOKERS Original Filed Sept. 4, 1947 5 Sheets-Sheet l June 1952 c. E. SHAFFER ASH REMOVER FOR STOKERS 5 Sheets-Sheet 2 Original Filed Sept. 4, 1947 June 24, E952 SHAFFER 2,601,332

ASH REMOVER FOR STOKERS Original Filed Sept. 4, 1947 5 Sheets-Sheet 3 IN VEN TOR. CHE 5752 E JHflFFtfE Patented June 24, 1952 ASH REMOVER FOR STOKERS Chester E. Shaffer, Arlington, N. ".L, assignor to KODDBIS Company, Inc., a corporation of Delaware Original application September .4, 1947, Serial No. 772,049. Divided and this application May 2, 1950, Serial No. 159,585

6 Claims. 1

This invention relates to coke stokers. More particularly the invention relates to an apparatus for removing ash from a Stoker-fired furnace.

The present invention embodies several features of the coke stokers embodied and claimed in my Patent 2,388,294 granted November 6, 1945 and in my patent application Serial No. 551,084 filed August 25, 1944, now Patent No; 2,453,162, of November 9, 1948. The features of these patents, however, are embodied in the present invention in such a way that the coke feed and ash removal are more positive and adaptable for different sizes of fuel. Further the furnace grateis kept freer of ash and the operation of the stoker is more quiet and clean.

The primary object of the present invention is to provide an ash removal apparatus for a stoker fired furnace which will automatically remove any ash and clinker discharged from the grate of the furnace without interrupting any operation of the furnace.

Another object is to provide an ash removal apparatus for a stoker-fired furnace which is effective in removing ash and clinker discharged from the furnace grate irrespective'of its character orhardness.

Another object of the invention is to provide a simple and effective ash removal means for passing ash from the ash bars of my aforesaid patents to an ash elevator for automatic removal.

A further object of the invention is to provide a stoker which may be installed on the floor level of a furnace without removingparts of the floor toaccommodate the fuel feeding or the ash removal apparatus.

With these and other objects and'features in view, the invention consists 'in the improved stoker hereinafter described and particularly defined in the claims.

The various features of the invention are illustrated in the accompanying drawings inwhich Figure 1 is a top plan view with parts broken away ofa stoker embodying the preferred form of the invention;

Figure 2 is a view in side elevation of the stoker shown in Figure 1;

Figure?) is a view in side elevation with parts shown in section taken on the line IIIIII of Figure 2 showing the ash removal conveyor;

Figure' l is a view in elevation with parts in section'taken on the line IV-IV of Figure 2 showing the supports for the coke bin conveyor;

Figurebis a perspective view of the hydraulic drive mechanism and the connectionsbetween the hydraulic cylinder and the other moving parts of the stoker which are operated therefrom;

Figure 6 is a sectional view of the valve for controlling the operation of the hydraulic cylinder with the ports of the valve diagrammatically illustrated.

Thepresent invention is designed and adapted particularly for feeding fuel to and removing ash from and controlling the combustion in a domestic house-heating furnace. The various parts and operation of the stoker may be briefly outlined as follows:

Referring more particularly to Figures 1, 2 and 3, coke is stored in a bin having a hopper bottom (not shown) with a feed bin conveyor In which extends under and forms the bottom of the hopper. The feed conveyor Ill advances coke from the bin to the opening of a stoker feed tube [2 (Figures 1 and 2) from which the coke is advanced to and I pushed as an underfeed upwardly into the central area of. the bottom of an upstanding stationary annular grate l4 mounted in the firebox of a furnace or boiler l3. The continued feed movement of the coke into the grateprovides an up and down motion of the fuel in the grate which acts to discharge ash through thegrate to fall into the ashpit of th furnace. Simultaneously with the movement of the fuela clinker breaker and ash removal ring l6 between the central fuelfeed and the periphery of the bottom of the grate is operatedto assist in discharging ash and clinker from the fuel bed into the ashpit of the furnace. The ash discharged into the rear of the ashpitis moved by a pusher Hi to opposite-sidesof the ashpit into the path of an ash feed conveyor consisting of reciprocably mounted horizontal bars or plates which are reciprocated to carry the ash out. of the ash box and to discharge it into the path of an ashremovalconveyor 22. The ashremoval conveyor discharges the ash through a flexible tube 24 into a receiving container 26 (Fig. 3).

If the fuel is pushed into the grate faster than it is burned, it will build up in the grate and come in contact with a fuelbed level controllerlll (Figures 1 and 2). The controller 28 consists of a high temperature metal contact member 30 secured to a rod 32 which is pivotally mounted in the wall of the furnace l3. As the controlling member 28 moves up and down, it operates an electric switch 35 mounted at the side of the furnace to open and close. an electric circuit for operatingamotor 38 which drives a hydraulic pump 40. .When the hydraulic pump is operated the driving mechanism for the coke feed and ash removal is continuously operated, so long as the pump is operated. When the control member is raised by contact with the fuel to a predetermined point the electric circuit is opened to stop the motor. At the time that the fuel in the grate falls below the predetermined level the electric circuit is closed and the motor continues to operate until the fuel in the grate is raised to a point to open the electric circuit. The fuel feeding operationtherefore will be continuous so long as the fuel in the grate is below a predetermined level.

The burning of fuel in the furnace is controlled by a thermostat 42 which is usually located in the house or room being heated. This thermostat in turn operates an electric switch to open and close an electric circuit for operating a damper control motor 45. When the thermostat calls for heat, the motor is operated to move an eccentric lever to pull cables 46 and 48 to open a stack damper 50 and draft doors 52 respectively. When the thermostat is not demanding additional heat the eccentric lever is moved back to operate the cables to close the stack damper and the draft doors at the front of the furnace. It will be seen that the fuel bed level controller and the thermostat operate independently of one another for controlling combustion but the operation of the fuel bed level control is dependent upon the heat demand as determined by the thermostat.

Detail description of the stoker parts The fuel conveyor I8 is made up of steel sides 54 (Figure 4) that are mounted on a stand 58. At the bottom of the sides 54 are angles 51 upon which a hardened steel plate 58 forming the conveyor is slidably mounted. This conveyor plate 58 extends into and forms the bottom of a hopper in the coke bin. The plate 58 (Figures 1 and 4) has a plate 68 attached to the top thereof from which projects a pin 62. The pin 62 fits into one end of a lever 64 (Figure 5) which is connected with a driving mechanism as hereinafter described. The conveyor plate 58 is given a slow reciprocating motion. Upon its backward stroke it slides under the fuel or coke and upon its forward stroke the coke moves forward with the plate. The forward end of the plate discharges the coke upon a deflector member 66 (Figures 1, 2 and 3) forming the rear end of the underfeed stoker tube I2. The forward end of the frame in which the bin conveyor is mounted rests upon a plate 68 (Figures 2 and 3) which is integral with the rear end of the stoker feed tube. The plate 68 and the front end of the conveyor housing are circular in form so that the conveyor housing may be mounted in an angular position with reference to the feed tube to provide for different locations of the coke bin with reference to the furnace.

The feed tube [2 (Figure 2) has a conveyor!!! slidably mounted therein. The conveyor plate is shown more particularly in Figure 5. The rear end of the plate is connected with a pusher plate 12 (Figure 5),'which in turn, is pivotally connected with a clevis on the front end of a piston rod 14. The coke which is discharged from the end of the conveyor plate 58 upon the deflector plate 68 falls upon the pusher plate 12 (Figures 1, 3 and 5). reciprocating movement. On the rear stroke of the plate the coke resting on the plates 12 and 18 is held from movement with the plates by the The plate 10 isgiven a slow deflector 68, but upon the forward movement of the plates '18 and 12 the coke is pushed forward. As the coke reaches the front end of the conveyor 78 it falls over a ram 16 at one end of the conveyor 18 (Figures 2 and 5) which ram is slidably mounted in the bottom of the feed tube. On the forward movement of the conveyor plate the ram 16 forces the coke across a curved face 18 of the feed tube [2 to force the coke up through the throat of the feed tube centrally up into the annular upstanding grate of the furnace from below. As the coke is forced up into the central area of the grate it moves up and falls back with the movement of the ram 15. A chord edge 88 (Figure'l) at the top of the feed tube throat projects outwardly and tends to hold the coke in an arched position in the fuel bed so that only a part of the coke moves downwardly when the ram is retracted. The ram 16 moves the coke upwardly through the central portion of the feed tube and the fuel in the central portion of the feed tube moves upwardly and downwardly with the movement of the ram. During combustion there is a shrinkage of the coke at the grate walls and the ash and impurities gradually travel down the upstanding face of the annular grate to the annular clinker breaker it. The fuel movement is thus an upward movement through the central portion of the grate and an outward and downward movement along the walls of the grate. In this movement the fine ash passes out through the spaces between the vertical bars of the grate and coarser impurities of ash or clinker are broken up or crushed by the clinker breaker ring I6. The clinker breaker ring [6 may remove fine ash as well as the coarser ash or clinker. t has been found that the upward and downward movement of the coke bed in the grate is necessary to get the line ash and clinker from the center of the fuel bed out to the annular grate and down to breaker. This up and down movement of the coke in the fuel bed with each stroke of the ram tends to move the ash from the fuel bed toward the grate bars so that the ash moves through the grate bars to be discharged into the ashpit of the furnace.

To assist in removing ash and clinker from the fuel bed an oscillatably mounted clinker breaker and ash remover ring is positioned below the grate l4 between the lower periphery of the upstanding annular grate l4 and the central fuel feed. The clinker breaker consists of a ring [6 having a series of teeth 82 on the upper surface thereof (Figures 1 and 5). The ring forms a portion of the grate and thus supports part of the fuel bed. The ring I5 is supported on top of a grate ring 84 which rests directly on top of the tube [2. The ring 84 is secured to the tube I2 while the ring I8 is slidably mounted on the ring 84. A pair of downwardly projecting lugs 86 are formed on opposite sides of the ring [6 which extend through openings 88 in the ring 84. The lugs have pins fixed therein which project into holes in each arm of a yoke 90 (Figure 5), which is positioned under the ring. The yoke 90 is pivotally mounted at its mid-portion in an arm 92 of a compound lever 94 which is pivotally mounted between flanges 96 projecting outwardly from the front end of the feed tube (Figure 2). A transversely extending arm 98 (Figure 5) on the compound lever 94 is connected with a driving link I00 which is connected with the driving mechanism, as hereinafter described. The ring I6 loosely fits in the ring 84 to leave a space by which ash and clinker may move around the outside of-th ring to be" discharged into the ashpit. On top of the ring84 is mounted a'grate ring I02 which has a groove in itsupper surface shaped to receive the lower end of the grate bars I4. Th grate bars inclinefrom the ring I 02 upwardly and outwardly sothat'the upper ends ofthe grate bars rest against thefireboxwall of the furnace.

A second outwardly extending arm I04 (Figures 2 and 5) on the compound lever 94 has the rear ash-pit pusher I8 attached thereto which pusher extends downwardly from the lever 94 in close proximity to the bottom of the ashpit but above and between the spaced apart ash bars for the purpose of moving the ash which falls from the grate at the rear of the ashpit into the path of the ash feed conveyors or bars 20.

The hydraulically operated driving mechanism is illustrated more particularly in Figures 1, 2 and 5. The pump for placing the driving fluid under pressure is submerged in a driving fluid in'chamber I05 which has a hydraulic liquid filling tube I08 and a cleaning tube I08. The pump draws fluid from the closed chamber and forces it through a valve mechanism IIO which is mounted within the chamber I05. The motive fluid flows from the valve I I 0 through a tube I I2 or tube H4 to a hydraulic cylinder H8 in accordance with the positionof the driving pistons H8, I20 Within the cylinder. When one of the tubes H2 or H4 is used-for driving the cylinder piston, the other tube is used for exhausting the fluid from the opposite side of the piston. The fluid returning from the cylinder to the valve is exhausted through the valve into th chamber.

The construction and arrangement of the valve H0 is illustrated in Figure 6. The valve consists of a block having cylindrical plungers H8 and I20 slidably mounted within the block. Each plunger is provided with three faces which are arranged to open and close ports in the block I I0 to provide different paths of flow of the hydraulic fluid through the valve. The pump 40 is diagrammatically illustrated in Figure 6 as opening into a port I22 under the plunger H8. The fluid entering the port I22 flows through a port I24 to the tube I I4 and thence through the tube into the cylinder H5. While the fluid is forcing the plunger to move through the cylinder, fluid from theother side of the cylinder flows through the line H2 into a port I 26 and thence through a port I28 and passage I30 in the block down into the storage chamber I05. At the sam time oil flows from the port I24 through a passage I32 to a port I 84 behind the end of the plunger I 20, thus holding the plunger I20 to the right in' the position shown in Figure 6. Also the oil from the pump flows through a passage I35 into a port I38 behind the plunger I20 and this oil also passes through a port I40, through passage I42 into a port I44 against the end of the plunger H8. The plunger H8 is held in its position by spring pressed detent I40 which rests against a central shoulder on the plunger. The pressure of the spring will hold the plunger I I8 stationary under the ordinary operating pressure of the pump. However, when the piston reaches the end of its stroke the continuous operation of the pump 40 tends to build up the oil pressure and when this pressure rises above the usual or operating pressure, then the fluid flows from the port I48 through the passage I42 to the port I44 and=moves the plunger I I8 to the left (viewing Figure 6). When the plunger H8 moves to the left the port I22 is positioned on the right side 6 ofthe central face of the plunger so that the fluid may flow through the port I28and a passage -I48 to a port I50 behind the plunger I20. The operation of the plungers H8 and 120 is such that the plunger H8 moves from one position to the other before the plunger I20 follows in this movement. I With this operation the ports are all completely closed or completely open. When the plungers move to the left, ports I52 and I54 are open to passage I56 which permits the oil to flow into the sump. It will be understood that when the plungers are shifted to the left the pressure oil flows through the valve to the line H2 and oil exhausted from the cylinder flows from the line H4 into the port I44 and thence through the passage I56 to the sump in the pressure chamber I05. Rubber bumpers I58 are mounted on the inner ends of the nuts I60 which close the passages in which theplungers H8 and I20 are mounted so that the plungers strike against the bumpers and thus deaden the sound of the valve shifting. The valve arrangement which is described above is important in that the valves are reversed Whenexcessive oil pressure develops in the feed lines. This arrangement acts asa safety measure so that if the driving mechanism is prevented from making a full stroke by some obstruction to the fuel feed or ash removal the driving mechanism will be reversed to relieve the pressure and therefore an excess pressure will not be exerted upon the driving mechanism. A locking pin I82 is mounted in the central portion of the valveblock H0 and moves between the plungers H8 and I20. This detent prevents the plunger I20 from moving to the left (Figure 6), when oil is being forced into the cylinder through the tube H4. When the plunger H8 has been moved to the left the oil entering through the port I22 flows through the port I26 and passage I43 to the port I50. This oil moves the plunger I20 to the left. As the plunger I20 moves to the left the detent I62 is raised. Thedetent I82 thus insures that the plunger H8 will move in each direction in advance of the following movement of the plunger I20. The same fluid pressure tends to raise the detent I02 and also acts to raise the detent I48.

A piston mounted in the cylinder H5 is connected with a pusher plate I2 by the piston rod 74 (see Figures 1 and 5). The movement of the cylinder piston which drives the feed tube conveyor furnishes the power for operating all of the stoker mechanism.

To drive the coke bin conveyor a cross bar I66 (Figures 1 and 5) is attached to the bottom of the conveyor plate I0 so as to move with the conveyor plate. A connecting rod I68 is pivotally connected to the right hand end of the bar I66 (viewing Figure 5) and the other end of the link is connected with a lever I70 which is secured to a rotatable ash conveyor plate II2 having ash moving means in the form of a quadrant cut out area 204. The ash conveying quadrant cut-out plate and lever I10 are pivotally mounted on the bottom of the feed tube frame I'I4 (Figure 2) for oscillation near an ash receiver 208 by means of a'plate I16 and pin I18 (Figures 1, 2 and 5). An upwardly extending pin I is mounted in the rod I68 to receive a slotted end I82 of a link I84. The link I84 is connected with a lever I86 which is fixed on a pin I83 (Figure 5) pivoted in a bearing I which is attached to the side of the 7 feed tube. A lever I02 is secured to the upper end ofthe pin I88 so as to be movable'therewith.

The lever I92 is pivotally connected with the link 64 so that the movement imparted to the link I84, levers I86 and I92 is imparted to the link 64 for giving the reciprocating movement to the coke bin conveyor plate 58. The slot I82 in the link I84 is provided With a threaded bolt I94 by which the amplitude of, or the extent of the movement of the coke bin conveyor may be varied. It has been found in practice that the stroke of the coke bin conveyor should be shorter than the stroke of the feed tube conveyor in order to properly allocate the desired amount of coke being fed to the fuel bed.

To operate the clinker breaker I6 and ash pusher I8 the link I which is connected with the compound lever 94 has a pin and slot connection with the left hand end of the bar I66 (viewing Figure The link I60 has a slot and pin connection with a pin I96 mounted in the rod I66 by which the length of stroke of the crusher may be varied.

The coke feed tube has a circular cross section at the front side of the grate so that ash which falls in the vicinity of the feed tube flows down to the floor of the ashpit. The ash pusher I8 moves the ash which falls at the back of the grate to the sides of the ashpit into the path of movement of the ash feed conveyor bars 28. The ash feed conveyor bars consist of two reciprocable bars or plates which are slidably mounted in guides 20!] positioned under the feed tube (Figure 2). The front ends of the flat bars or plates 20 are connected with pins 202 that are mounted in the face of the rotatable ash conveyor quadrant cut-out plate H2. The movement of the link I68 and lever I'IB oscillates the plate I12 to give a reciprocating motion to the flat conveyor bars or plates 20. The bars or plates 20 are spaced from each other on opposite sides of the feed tube and move in opposite directions. The slow reciprocating motion of the bars or plates 20 carries the ash from the ashpit of the furnace forwardly to the rotatable ash conveyor quadrant cut-out plate H2. The rotatable conveyor plate has a quadrant cutout section 234 which acts to move the ash into ash receiver 258 for the elevator cups 2% of the ash removal elevator 22. The position of the elevator cups with reference to the quadrant cut-out plate I12 is shown in Figures 1 and 2. Each oscillating stroke of the conveyor quadrant cut-out plate I'I2 acts to move ash from one of the bars or plates 29 to the ash receiver 298 at the bottom of the elevator, whence the ash is picked up by the cups 205.

The construction of the ash removal elevator is illustrated more particularly in Figures 1, 2 and 3. A boot 208 constructed to receive the lower end of a frame 2H] for housing the ash removal elevator is attached to the frame of the feed tube immediately under the front end of the coke bin conveyor. The boot is constructed and arranged so that it may be attached to either side of the feed tube frame in order to permit the elevator to be located in any desired arrangement of the housing for the heating furnace. The boot constitutes the ash receiver 208 for the elevator 22. The elevator consists of a chain 2I2 which runs between sprockets EM and 2I6 that are rotatably mounted on axles 2I8 and 220, respectively. The axle 2I8 is mounted in hearings in the boot 298 and the axle 2211 is mounted in bearings in the frame 2H1. The axle 220 is the driving axle for the elevator. To drive the elevator a cable 222 (Figure 5) is connected with the left hand end of the bar it (Figure 5) and extends to a pulley 224 pivotally mounted in the boot 208. The cable passes over the pulley 224 and is connected with a chain 226 which passes around a clutch pulley 228 on the axle 220. Upon the forward stroke of the feed tube conveyor 10 the cable 222 operates the clutch 228 to impart an active stroke to drive the elevator for a predetermined distance. Upon the return stroke of the feed conveyor 20 cable and clutch are moved with an idle stroke in a reverse direction by a coiled spring 230 which is connected to the chain 226 and the elevator frame 2 I 0. Accordingly the elevator is given an intermittent stepwise motion which corresponds to the feed stroke of the feed tube conveyor. A series of cups 206 mounted on the chain 2I2 move into the path of the ash in the boot 208, advanced by the ash conveyor bars and carry the ash to the outlet discharge tube 24 and receiver 26. I

With the construction outlined above, it will be seen that all of the stoker parts are mounted on frames which rest on the floor level of the furnace. The coke bin conveyor may be adjusted to angular positions to permit different locations of the coke bin with reference to the furnace. The ash elevator may be mounted on either side of the coke feed tube. Two ash receivers 26 are positioned on the floor at the side of the ash elevator. An empty receiver thus may be readily placed under the tube 24 when one container has been filled.

The movement of the coke to the furnace grate and the removal of ash and clinker from the ashpit are carried out by flat reciprocating bars or plates 20, and the oscillatable quadrant cutout plate. Such an ash conveyor has a distinct advantage over screw conveyors or continuously operating belts, because such conveyors do not become clogged with the different kinds of material being conveyed.

The hydraulic drive is positive and quiet and still will automatically change the stroke or reverse itself if the driving parts become clogged.

This application is a division of my pending application relating to Coke Stokers, Serial No. 772,049 filed September 4, 1947.

The preferred form of the invention having been thus described, what is claimed as new is:

1. An ash removal apparatus for a stokerfired furnace, comprising: a furnace, a grate mounted in the furnace, an ashpit in the furnace below the grate, an ash, elevator positioned a substantial distance from the furnace, an ash receiver at the bottom of the elevator, an ash conveyor extending between the ashpit and the ash receiver at the bottom' of the elevator, said ash conveyor comprising reciprocable fiat bars mounted adjacent the ash pit in position to receive ash discharged from the grate and a rotatable plate having ash moving means thereon and mounted for oscillation near the ash receiver, said fiat bars being connected with said rotatably mounted plate to push ash advanced by the bars over the rotatable plate to the ash moving means thereon for discharge thereby to the ash receiver of the ash elevator.

2. Apparatus as claimed in claim 1, and in which driving means are connected with the rotatable plate for oscillating the same and thereby also imparting a reciprocating motion to the reciprocable flat cars connected to the rotatable plate.

3. Apparatus as claimed in claim 1, and in which an oscillatable ash pusher is mounted for oscillation in position in the ashpit between and above the reciprocable flat ash bars to push ash into the path of movement of the ash bars.

4. Apparatus as claimed in claim 1, and in which the ash moving means on the rotatable plate comprises a quadrant cut-out portion of the rotatable plate.

5. Apparatus as claimed in claim 1, and in which means are provided for driving the ash bars and the rotatable plate to impart a reciprocating motion to the ash bars and an oscillating motion to the rotatable plate, and in which said driving means is connected with the elevator by a reciprocating member and a member driven thereby which has an active and an idle stroke, to operate the elevator on the active stroke to carry ash out stepwise to an outlet on each reciprocation of the ash bars.

6. Apparatus as claimed in claim 5, and in 10 which the ash elevator is an endless chain and a cup elevator having a clutch drive with an active and idle stroke to give a step by step movement to the elevator when the ash conveyor is operated.

CHESTER E. SHAFFER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

